1. Field of the Invention
The present invention relates to a digital still camera which reduces photographed images and forms reduced image data for indexing use.
2. Description of the Related Art
Digital still cameras are known wherein photographed image data is recorded, without compression or alteration of the data. Further, digital still cameras are known wherein the photographed image data is compressed and recorded as frame units on a recording medium such as a memory card.
In order to provide confirmation of the kind of image data which is stored on a memory card, typically one image frame at a time is played back and displayed on a monitor or the like. However, when there are many frames of image data recorded on a memory card, the time required to display and confirm one picture at a time becomes long. In the future, when the capacity of the memory card increases and, as a result, the amount of image data which can be stored is increased, it will be required that the time for playback and display of image data (i.e, the indexing time) be shortened.
It is possible to shorten the indexing time by reducing the photographed image data and by displaying plural reduced images at the same time. When forming reduced image data for playback and display, i.e, indexing, generally, the images which are recorded in the memory card are reduced serially, one image frame at a time. For example, as seen in FIG. 9B, when forming reduced image data for indexing use, four frames can be displayed at one time. When forming a first indexing picture, the image data corresponding to the 1st frame through the 4th frame in the memory card are reduced and, when forming a second indexing picture, the image data corresponding to the 5th frame through the 8th frame in the memory card are reduced. Subsequent reduced image data for indexing use are similarly formed in turn.
However, as seen in FIG. 10A and FIG. 10B, the image data includes not only image data corresponding to frames photographed at the usual camera attitude (i.e., with the camera in an upright position), but also image data corresponding to frames which have been photographed at a camera attitude inclined 90.degree. to the right or to the left from the upright position. When the image data is reduced one image frame at a time, as in the prior art, the image data corresponding to a photograph taken with the camera in the upright position poses no particular problem when forming reduced image data for indexing. However, as shown in FIG. 10B, when the direction of image data corresponding to a photograph taken at camera attitudes of 90.degree. to the left or to the right from the upright position (sideways position photography), the indexing picture becomes more difficult to view.
Further, according to the prior art, when continuous photography is performed, and the reduced image data for indexing use is formed in turn, the image data corresponding to the successive photographs taken during continuous photography may be formed across two reduced images, and therefore the continuous photographs are difficult to view. For example, as shown in FIGS. 11A-11C, the 2nd frame through the 5th frame of image data recorded on the memory card correspond to pictures taken in the continuous photography mode. When three frames (FRAMES 2-4) are formed in the first reduced image (INDEX PICTURE 1) as shown in FIG. 11B, and one frame (FRAME 5) is formed in the second reduced image (INDEX PICTURE 2), as shown in FIG. 11C, the progression of the sequence of continuous photographs is difficult to view and to understand.
Furthermore, it is desirable for the photographs to be rearranged according to event, date, etc., after they have been photographed, in order to easily view the photographs.